Pretty big storm was it then? Tell me
more.The storm of the 15/16 October
1987 is probably Englandís most famous (and infamous!!) weather event of
the 20th century. With gusts between 70 and 100 knots, this was south-eastern
Englandís worst storm since the Great Storm of 1703 and as if this wasnít
enough the storm also killed 18 people and an estimated 15 million trees
were lost.

Why all the fuss? It's not like it's never
wet and windy in England is it?Not like this it isnít! However,
the October 1987 storm is more famous because of the public perception
that it was less than adequately forecast and for being synonymous with
BBC weatherman Michael Fish than for the damage it caused.

Oh yes, Iíve heard about this. Didnít
he say there wouldnít be a hurricane and then there was one.Well, thatís how many people
remember the forecasts before the storm, but it's not quite the whole story.
In a broadcast prior to the storm Michael Fish, responding to a viewerís
query, assured viewers that a hurricane which had just affected parts of
the USA would not affect Britain (it didnít). He then added, ďbut having
said that, actually the weather will become rather windyĒ. Which, of course,
it did.

It seems that in the aftermath
of the storm some people, including part of the British media, conveniently
chose to ignore the fact that Michael Fish had mentioned that it would
become windy over at least part of the UK and instead chose to focus on
the part of the broadcast where he mentioned the hurricane and made a bit
of a scapegoat out of the chap, thus making him synonymous with the October
1987 storm.

Even so, wasnít 'rather windy' a bit of
an understatement?It was really. Whilst the
forecasts for the British coastal waters werenít too bad, over land the
strength of the winds were really not anticipated until quite late on,
so based on the information to hand Ďrather windyí probably seemed an appropriate
thing to say at the time.

Bear in mind that in the days
leading up to the storm all the information available to forecasters suggested
that the zone of strongest winds would just miss the English mainland.
Also, the days before the storm had been rather wet and some places were
close to flooding. Consequently the emphasis of the forecasts were on rain
and the strong possibility of flooding rather than the wind.

Left: Figure One: The
track of the Great Storm 15-17th October 1987

So, meteorologically what happened?Weatherwise October 1987 started
off fine and dry but quickly became unsettled and wet. In the days leading
up to the storm an area of low pressure lingered to the west of Ireland
and its associated frontal waves crossed Britain from time to time producing
spells of wet weather.

It seems that interaction between
one such frontal wave near north-western Spain, an area of low pressure
(also near north-western Spain), warm air flowing eastwards out of Hurricane
Floyd (located just east of the USA), warmer than normal sea temperatures
in the Bay of Biscay and cold air moving south from Iceland towards Iberia
allowed the low near north-western Spain to deepen rapidly to form the
'Great Storm' and then move (very quickly for a low of this size) north-eastwards
to the northern North Sea via north-western France and England during the
15 and 16th October 1987 (see figure one). The cold air moving south from
Iceland towards Iberia and the warm air flowing out of Hurricane Floyd
near across the Atlantic Ocean into Iberia created an exceptionally large
temperature gradient over the Atlantic Ocean. When the low and frontal
wave near north-western Spain met this temperature gradient they were able
to deepen and develop rapidly and move quickly north-eastwards wreaking
havoc on the way. Warmer than normal sea temperatures in the Bay of Boscay
will have given the storm extra energy and moisture.

Left: Figure Two: Highest
recorded gusts (in knots) during the Great Storm 15/16 October 1987

So, what was the weather like during the
storm then? Pretty windy Iíll wager?Obviously the main feature
of the storm was the high winds. Wind speeds over southern England
began to rise after the passage of the stormís warm front during the second
half of the evening of the 15th (see figure one) and were gusting to 70
knots along the south coast of England by 0000 GMT. During the early hours
of the 16th the stormís cold front passed and it was during the few hours
immediatly after the passage of the cold front that most places had their
windiest weather - most areas affected by the storm recorded their highest
winds between 0200 and 0600 GMT. Winds went on to gradually ease between
0600 and 0900 GMT.

South-eastern England was worst
affected by the high winds and with a gust of 100 knots Shoreham (on the
south coast in Sussex) recorded England's highest gust during the storm.
Further along the coast Langdon Bay (near Dover) experienced gusts of 90-95
knots, as did central London. Some places in south-eastern England registered
gusts of 70 kts for 3-4 hours in a row. Figure two shows where the highest
gusts were.

The wind direction during
the storm was also of interest; in south-eastern England, where the most
damage occurred, the strongest winds were southerly. In other parts of
the country affected by the storm, East Anglia for example, there were
two distinct peaks in the wind one from the south roughly between 0200
and 0400 GMT and another from the south-west approximately between 0500
and 0800 GMT. This in itself was quite unusual because the strongest winds
over the UK usually come from directions between west and south-west rather
than from the south to south-west.

Also striking were the high
temperatures observed during the storm. The storm brought with it some
very mild air over southern and eastern England, where many places registered
temperatures between 14C and 17C during the night of the 15/16 October.
There were also some spectacular temperature rises during the storm. For
instance, the temperature at Heathrow Airport was 8C at 1800 GMT on the
15th and 17C at around 2100 GMT. At one point the temperature here rose
by about 7C in just one hour, the largest one hour temperature rise recorded
here in at least 37 years.

Finally, there were some record
breaking pressure rises after the storm. As the storm moved away
north-east during the early hours of the 16th pressure rose very quickly
over southern England. Typically pressure rose by between 19 and 25mb in
3 hours, and this is the largest 3 hour pressure change on record in the
UK.

Quite a lot of damage then?Oh yes. Most of the damage
occurred south of a line joining Southampton with London and Norwich. This
roughly coincides with the region where mean winds of 40 knots or more
and gusts of 80 knots or more were recorded. 18 people were killed during
the storm, half of them in the far south-east of England. Had this storm
occurred during daylight hours rather than overnight the death toll would
undoubtedly have been higher. An estimated 15 million trees were lost.
This figure would probably have been lower if trees hadnít still been in
leaf and the ground hadnít already been saturated by rain earlier in the
previous few days. One in six householders in south-eastern England put
in insurance claims after the storm and damages cost around £1500 million.

Lucky this sort of thing doesnít happen
very often then?Too right. This sort of thing
hardly ever happens in south-eastern England. South and east of a line
joining the coast of East Anglia with London and Southampton both mean
winds and gusts with return periods of 200 years occurred!

Further, the strongest winds
over the UK usually come from directions between west and south-west rather
than south to south-west as occurred during the storm. If you also take
into account the fact that October isnít one of the windiest months of
the year it becomes clear that the chances of a storm of this magnitude
in this area in October is really quite small.

Still, powerful storms do happen
over south-eastern England every now and again; during the last 800 or
so years comparable storms affected the region on the 7/8th December 1703,
28th February 1662 and 23rd January 1362.

The storm didnít just affect England did
it though? What about the Netherlands and France for example?South-eastern England wasn't
alone in being affected by the Great Storm. Parts of northern and north-western
France reported stronger gusts than those in England, and in fact the highest
gust recorded during the storm was 117 knots at Pointe du Raz in Normandy.
Further east gusts of 60-70 knots were reported in parts of Belgium.

The
storm also brought some very windy weather to the Netherlands (see figures
two and three). In coastal areas south to south-westerly winds reached
34-40 knots between 2100 GMT on the 15th and 1500 GMT on the 16th and peaked
at 48-55 knots between 0600 GMT and 1200 GMT on the 16th. During the night
of the 15/16th gusts were reaching 40-50 knots but then late in the night/early
in the morning both mean winds and gusts over the Netherlands increased.
Gusts between 60-70 knots were registered in south-western coastal areas,
whilst in some north-western coastal parts winds gusted to 70-80 knots.
IJmuiden repored the strongest gust (80 knots), whilst Den Helder, Warmehuizen
and Terschelling werenít too far behind with 72-73 knots. Hoek van Holland
and Huizen, meanwhile, recorded gusts of around 66 knots. Elsewhere gusts
of 45-60 knots were widely reported.

As well as bringing the Netherlands
some very windy weather, the storm also brought with it some rather warm
air; during the night temperatures gradually rose and in some places the
night of the 15/16th was the mildest night of the month. By sunrise on
the 16th temperatures were around 18 or 19C in most places and at around
20C Eindhoven, Rotterdam and Valkenburg were the Ďhot-spotsí. Most of the
Netherlands went on to record their maximum temperature on the 16th at
the height of the storm! Places roughly to the south and west of a line
joining Venlo, Utrecht and Den Helder recorded their maximum temperature
for the 16th between 0500 and 0700 GMT, whilst elsewhere the maximum temperature
was reached between 0700 and 0900 GMT. Incredibly some places in the province
of South Holland (in the western Netherlands - Rotterdam is the main city
in this province) recorded their highest temperature of the whole month
during the storm!! Meanwhile, the troughs near France in figure three went
on to produce some thundery showers over the Netherlands later in the day
on the 16th.

Above:
Figure Three: The seemingly rather unlikely synoptic situation in which
some parts of the Netherlands recorded their highest temperature in the
whole of October 1987!